"A book collector ought as I conceive," Gladstone wrote to Bernard Quaritch on 9 September 1896, "to possess the following six qualifications: appetite, leisure, wealth, knowledge, discrimination, and perseverance. Of these I have only had two, the first and the last, and these are not the most important." A voracious, persevering, and pragmatic collector, Gladstone amassed a private collection of more than thirty thousand volumes and spent the closing years of his life carefully planning to make these books accessible to the public at what was to be his memorial repository, Saint Deiniol's Library.

Besides actively establishing and administering several other libraries as well as drafting important legislation for the print industry and a prophetic analysis of book storage, the four-term prime minister was a leading combatant in the Homeric Question, his age's great Battle of the Books. As he was collecting, arguing about, and cataloguing books, Gladstone recorded these...